As exemplarily shown in FIG. 6, a conventional inspection apparatus includes: a movable mounting table 1 for mounting thereon a target object (e.g., a semiconductor wafer) W; a driving mechanism 2 for moving the mounting table 1 in a horizontal and a vertical direction; a probe card 3 disposed above the mounting table 1; an alignment mechanism 4 for performing alignment between a plurality of probes 3A of the probe card 3 and a plurality of electrode pads of the semiconductor wafer W on the mounting table 1; and a control device 5 for controlling various devices including the mounting table 1 and the alignment mechanism 4. After the probes 3A of the probe card 3 and the electrode pads of the semiconductor wafer W on the mounting table 1 are aligned to be in contact with each other, the semiconductor wafer W is overdriven in such a way that electrical characteristics of the semiconductor wafer W can be inspected by using a predetermined contact load under the control of the control device 5.
The alignment mechanism 4 has a first camera 4A for imaging the semiconductor wafer W on the mounting table 1, a second camera 4B for imaging the probes 3A of the probe card 3, and image processing units 4C and 4D for image-processing of images captured by the first and the second camera 4A and 4B. The alignment between the electrode pads and the probes 3A is carried out based on the respective captured images of the electrode pads of the semiconductor wafer W and the probes 3A of the probe card 3. Further, a reference numeral 4E in FIG. 6 represents an alignment bridge.
For example, during a high-temperature inspection of the semiconductor wafer W, the semiconductor wafer W on the mounting table 1 is heated to, e.g., about 150° C., by a temperature controlling mechanism installed in the mounting table 1 and, also, the electrode pads of the semiconductor wafer W on the mounting table 1 are aligned with the probes 3A of the probe card 3 by the alignment mechanism 4. After that, the electrode pads and the probes 3A are made to contact with each other by raising the mounting table 1 with the use of an elevation driving mechanism and the semiconductor wafer W is overdriven so that the electrode pads and the probes 3A are electrically brought into contact with each other by a predetermined contact load. Thereafter, the electrical characteristics of the semiconductor wafer W are inspected at a high temperature of about 150° C.
In an initial stage of the inspection process, although the semiconductor wafer W is heated to about 150° C., the probe card 3 is not heated and, thus, a large temperature difference exists between the semiconductor wafer W and the probes 3A. Accordingly, when the probes 3A are brought into contact first with electrode pads of the semiconductor wafer W during the inspection, the probes 3A are thermally expanded while being directly heated by the semiconductor wafer W on the mounting table 1. Further, the main body of the probe card 3 is thermally expanded while being gradually heated by the heat transmitted from the semiconductor wafer W side. As the devices in the semiconductor wafer W are repetitively inspected, the temperatures of the main body of the probe card 3 and the probes 3A gradually increase. Accordingly, the probes 3A are extended from a state shown in FIG. 7A to a state indicated by a fine line in FIG. 7B, and the tip positions thereof are gradually displaced from the original positions. Therefore, if the semiconductor wafer W is overdriven by a preset overdrive amount, the contact load from the probes 3A becomes excessive, which may damage the probes 3A and/or the electrode pads P. Moreover, due to the thermal expansion of the probe card 3, a long period of time is needed until the tip positions of the probes 3A become stable.
To that end, for a high-temperature inspection, the probe card is first brought into dimensional stabilization by completing the thermal expansion of the probe card by preheating, and then the high-temperature inspection is carried out thereafter. However, recently, the probe card has been kept being scaled up, and therefore, the preheating takes a long period of time, e.g., 20 to 30 minutes. Thus, in a technique described in, e.g., Patent Document 1, the probes are brought into a direct contact with the semiconductor wafer set to a high temperature for inspection and the probe card is preheated from its vicinity.
(Patent Document 1) Japanese Patent Laid-open Application NO. 2007-088203
In the technique of Patent Document 1, the probe card is hardly thermally expanded during the high-temperature inspection and, hence, a stable contact load between the probes and the semiconductor wafer can be obtained by a predetermined overdriving amount. Accordingly, the probe card or the semiconductor wafer can be prevented from being damaged. However, the technique of Patent Document 1 is disadvantageous in that the additional preheating time is required in addition to the inspection time and, hence, the total inspection time is increased by as much as the preheating time. In addition, it is disadvantageous in that the positions of the probes 3A are changed and the probe card is cooled while the mounting table 1 is separated from the probe card 3 in order to exchange a target object or perform the alignment.